please help diagnose vag com results (o2 readings)

[sparktikus]

Hi
i have a problem withh 1.6l gas 2001 beetle
CEL Is on
vag com reading
16556 - Fuel Trim: System Too Rich: Bank 1
po172 - 35 -10 - - - Intermittent

symptoms are car will dip revs then settle when idling at start up, sometimes stalling
and smoke too much from tailpipe
i have repaired a vacuum leak previously and dont think there is any more vac leaks
i have tested maf sensor as outlined on ross-tech website monitoring group 2 and good results back so this i assume is good

the problem i have is with suspect o2 sensors
in group 32 of vag com the first figure recorded is at 0.5% and second figure is at zero
ive never seen the second figure move from zero
is this the only way to monitor o2 sensors . Is one of these or both at fault causing rich fuelling , is this right? are there any more tests i can do?
thanks

[LadybugEwa]

Bank one is the pre-cat O2 sensor. That sensor has major input into the fuel/air ratio.

[sparktikus]

from these readings is this sensor faulty?
are or there any more tests i can do with vag?

also in "readiness" setting on vag
everythings passed apart from
catalytic convertor
failed or incomplete &
oxygen sensors
failed or incomplete

[savethebluths.org]

If you have smoke coming from your tailpipe it could be a head gasket problem with coolant/oil burning which would explain the smoke and the loss of pressure could explain the misfires.

But then again, it could just be an o2 sensor

[sparktikus]

im not loosing any coolant
and it smells gassy not oily
so i think my problems are purely just down to being over rich.
Just need some help diagnosing with vag com
why doesnt the second reading in group 032 move from zero
is this at fault?
but if it was surely it would have flagged up a seperate fault?
are there any more blocks i can look at to diagnose bad sensors? or should i just swap both of them out?

thanks